Electrical coil

ABSTRACT

An electrical coil having a strand of conductive material formed into a series of loops lying substantially in the same plane to produce a field substantially perpendicular to the plane.

Umted States Patent 11 1 1111 3,717,835 Roadstrum [451 Feb. 20, 1973 [51 ELECTRICAL COIL 3,085,899 4/1963 [76] Inventor: William H. Roadstrum,9 Juniper Lane, Holden, Mass. $305k 2,1967 [22] Filed: Feb. 24, 19703,372,358 3/1968 pp No 13 9 3,413,716, 12/1968 Schwentz et al ..336/200XFOREIGN PATENTS OR APPLICATIONS 1 335/213, 336/129; 566,894 11/1923France ..336/189 336/ 1 3 336/232 286,047 11/1927 Great Britain..336/l89 [51] Int. Cl ..l101f 27/28 [58] Field of Search ..336/205,206, 189, 190, 191, Primary Examine, Thomas Kozma 336 232, s4, 87,200,225, 232, 115, 129 Ammey N0man mods,

[56] References Cited [57] ABSTRACT UNITED STATES PATENTS An electricalcoil having a strand of conductive 1,661,953 3/1928 material formed intoa series of loops lying substan- 2,522,731 9/1950 tially in the sameplane to produce a field substantially 2,550,891 5/1951 perpendicular tothe plane. 2,830,212 4/1958 2,942,212 6/1960 Mynall ..336/200 X 9Claims, 24 Drawing Figures pmmgmtsolms sugar 3 or 4 FIG-J3PATENTEDFEBZIOISB' v $711835 sum u or 4 vve null) 85 k FIG 22 i FIG 23 1ELECTRICAL COIL BACKGROUND OF THE INVENTION In the manufacture ofelectronic circuits, it has become common practice to produce them in aflat form which may be used as part of a complete electronic device as areadily-replaceable board. Although most electronic elements lendthemselves to flat construction, the element that has produced the mostdifficulty in the past has been the inductive reactance or electricalcoil. Because the coils of the past have been formed in three dimensions(usually as a closely wound helix), the bulk of these elements hasinhibited the progress of making electronic equipment as a flat board.These and other difficulties experienced with the prior art devices havebeen obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide anelectrical coil which can be used in the manufacture of electricalcomponents and assemblies, which are easy to manufacture, which havereduced bulk, in which the interconnection systems are simplified, inwhich testing is simplified, which facilitate the use of printed oretched circuitry, and which simplifies the design and layout ofcircuitry.

Another object of this invention is the provision of a coil which isflat and in which the turns are normal to the coil axis.

A further object of the present invention is the provision of anelectrical coil which adapts itself readily to ease of manufacture.

It is another object of the instant invention to provide an electricalcoil which is readily designed for use in flat circuitry. I

A still further object of the invention is the provision of anelectrical coil which lends itself to the use of unusual core and looparrangements.

With these and other objects'in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of anelectrical coil having a strand of conductive material formed into aseries of loops lying substantially in the same plane. Each loopoverlaps the loop preceding it and the loop following it in the seriesand means is provided insulating the strand from itself at points ofcrossing.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a perspective view of an electrical coil embodying theprinciples of the present invention,

FIG. 2 is an enlarged sectional view through the coil taken on the lineIIII of FIG. 1,

FIGS. 3 through 5 show various modified forms of the coil,

FIG. 6 shows the use of the coil of the invention in a device usingpermanent magnets,

FIG. 7 shows the use of the coil with a kinescope,

FIG. 8 shows the use of the, coil with a shielding device,

FIG. 9 shows the use of the coil principle in an electronics circuit,

FIG. 10 shows the use of the principle of the coil in anotherelectronics circuit,

FIGS. 11A and 118 show the manner in which the coil can be used in avariable transformer,

FIG. 12 is a sectional view of two coils having a shield to minimizecapacitive coupling,

FIGS. 13, 14, and 15 show a method of printing that can be used to makeup a coil embodying the principles of the invention,

FIGS. 16 and 17 show a method of constructing a modified form of theinvention,

FIG. 18 shows a modified form of the coil,

FIG. 19 shows laminations used in the coil of FIG. 18, and

FIGS. 20 through 24 show various modified forms of the invention.

I DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1,wherein are best shown the general features of the invention, theelectrical coil, indicated generally by the reference numeral 10, isshown as having a main body 11 formed of a nonconductive materialwhich,for the purposes of illustration, is shown as being transparentplastic. This main body is generally rectangular in shape and isrelatively thin, so that it has a plate-like configuration. Encapsulatedin the main body is an electrically-conductive strand 12 formed ofcopper or similar electrically-conductive material. An end 13 of thestrand extends from one end of the main body 11, while the other end 14extends from the other end of the body. Visible within the main body areloops 15 which lie substantially in the same plane. Each loop overlapsthe loop preceding it and the loop following it in the series of loops.Means for insulating the strand 12 from itself is provided and in thepreferred embodiment this consists of the material of which the mainbody 11 is formed by virtue of the fact that the strand portions arespaced where they cross.

In FIG. 2 it can be seen that, in order to cause the loops 15 to lie ina flat plane, it is necessary that each loop be slightly inclined to thegeneral plane of the main body 11 and that, in order for the materialfrom which the main body is made to act as insulation, the position ofthe wires are kept separate from one another. It will be understood, ofcourse, that, in some versions it may be desirable to coat theconductive material in order to allow the strands of the loop to contactone another for ease of manufacture and assembly.

FIGS. 3., 4, and 5 illustrate the manner in which the loops can bearranged with different spacing within the principles of the inventiomlnFIG. 3, the electrical coil 20 consists of loops 21, the junctionbetween adjacent loops consisting of straight portions 22. The coils aremounted on a supporting insulating'strip 23. In FIG. 4, the coil 24consists of a series of loops '25 joined by straight portions 26 whereinthe loops are much closer together than those shown in FIG. 3. In FIG.5, the loops 27 of the coil 28 are spaced even closer together thanthose in FIG. 4. Placing them closer together, of course, has the effectof increasing the mutual inductan'ce and the overall inductance of theelectrical coil, depending also, of course, on the total number ofloops.

In FIG. 6, an electrical coil 30 of the type shown in FIG. 1, liesbetween two permanent magnets 31 and 32 to form a system which can beused in a loudspeaker, for instance. The alternating current audiosignal is applied to the coil to cause the coil to move physicallybetween the poles of the magnets to produce the physical motionnecessary in the loudspeaker for producing the audible sound.

In FIG. 7, a-kinescope 33, such as the tube of a television set, isshown associated with two electrical coils 34 and 35 of the type shownin FIG. 1. In this case, the coils are used to produce an inductivefield in the body of the tube in such a manner as to control the streamof electrons passing along the tube to produce the visual image at itsface.

FIG. 8 shows the manner in which a coil 36 of the type shown in FIG. 1can be enclosed in a metal housing 37 for shielding. Leads 38 and 39extend from the housing for electrical connection to the coil which lieswithin. The housing 37 can be of a box-like or platelike configurationexactly conforming but larger than the shape of the main body of thecoil.

In FIG. 9, an electrical circuit 40 is shown being used with three coils41, 42, and 43 of the type shown in FIG. 1 with a core 44 extendingbetween them. The coils are associated with electron tubes 45 and 46 anda power source 47, while the output coil 43 is connected to a load 48.The circuitry is similar to conventional circuits but, of course, theuse of the flat coils makes it I possible to provide a flatconfiguration to the entire circuitry.

FIG. shows another circuit 50 being used with coils 51, 52, and 53 ofthe type shown in FIG. 1. A core 54 lies between the coils 52 and 53 anda load 55 is connected across the coil 53. The coils 51 and 52 areassociated with electron tubes 56 and 57 as well as a source 58 ofpower. I

FIG. 11 shows the manner in which two coils 60 and 61 can be used toprovide a variable transformer. The coils are mounted so as to bephysically adjustable relative to one another with their flat sidesfacing.

FIG. 12 shows another method of shielding between two coils 62 and 63,both of which are constructed similar to that in FIG. 1. A Farradayshield 64 is interposed between the two plate-like coils.

FIGS. 13, l4, and show various layers of a printed-circuit electricalcoil formed in accordance with the invention. In FIG. 13, the body 65 ofinsulating material is shown as carrying the loops 66 having straightportions 67 which are interrupted where they are crossed by anotherportion of the loop. FIG. 14 shows insulating patches 69 to be printedon the same body 65, the coils being omitted for clarity ofunderstanding.

FIG. 15 shows the body 65 carrying printed thereon jumpers 71 ofconductive material having enlarged ends 72 which extend past thepatches 69 and make contact with the broken ends of the straightportions 67 associated with the loops 66 in FIG. 13. It can be seen thatall of the elements of the coil are produced on the same bodysuccessively by the printed circuit method so that the result is in anelectrical coil which is quite thin and which is made by the printedcircuit method.

FIG. 16 shows a portion of an electrical coil having a body 73 to whichare applied core elements 74 made by.

the printed circuit method or other method and making use of ironpowders or laminations. In FIG. 17 it can be seen that to the body 73has been added a strand 75 formed into overlapping co-planar loops 76.The core elements 74 are located in spaces provided by fairly widespacing between adjacent loops.

In FIG. 18 is shown a method of providing an electrical coil 77 with asuitable core. The coil is of the type shown in FIG. 1, but the core 78is made up of a plurality of laminations or elements 79 formed ofsuitable sheet steel and cemented in place in interlocking relationshiparound the coil. FIG. 19 shows the specific shape of the elements 79 andshows how they are arranged alternately on the coil.

In FIGS. 20 to 24 are shown various modifications of the looparrangement. FIG. 20, for instance, shows 'a coil 80 having loops 81which are arranged in closely adjacent pairs with rather wider spacesbetween pairs in the series. FIG. 21 shows a coil 82 having loops 83which are generally square in shape but are provided with straightportions 84 connecting the loops. In FIG. 22 is shown a coil 85 whoseloops 86 are hexagonal in shape. In FIG. 23 a coil 87 is provided with aseries of loops 88, 89, 90, and 91 which are successively smaller as oneprogresses along the series from one end of the strand to the other;this, ofcourse, could result in an inductance field of a desiredpeculiar shape. FIG. 24 shows a coil 92 having a series of loops 93which are arranged in the same general plane, but the centers of whichform a curve, so that the inductive field would be in the shape of acluster. This coil would be similar to the coil shown in FIG. 1, butwith a curve in the plane of the plate-like main body.

It can be seen, then, that the present invention involves a new form ofcoil or inductance which can be employed advantageously in many wayswith or without core materials. It can be used by itself or insituations requiring coupling with other coils. It can be used open orshielded. It is very useful in the production of electronic orelectrical components and assemblies in a two-dimensional form or in aform that is as limited in its third dimension as is possible orpractical consistent with other electrical or mechanical requirements.Such flat components and assemblies can ease manufacture, reduce bulk,simplify interconnection systems, simplify testing, facilitate use ofprinted or etched circuitry, speed design and layout, and have otheradvantages. This coil can be configured in a practical manner in avariety of ways for obtaining a desired inductive field. The coil can beeasily constructed by winding the strand of wire in essentially oneplane with a circular motion combined with a longitudinal motion in thesame plane. This produces a form similar to the forms in the old Palmermethod of penmanship in which circles were inscribed on a paper whilethe arm was moved uniformly along the line on the paper. Naturally,where the coil crosses itself, it is necessary that the coil wire beinsulated or that some means be taken to prevent the conductor fromtouching itself at these points. Such means can include inclining theplanes of the loop of the coil slightly out of the plane of the coil orby making a slight detour of one wire around the other. The densityofthe coil winding so constructed can be easily varied by changing therate of longitudinal motion compared to the circular motion forming thecoil turns, and this procedure will produce the varied results shown inFIGS. 3, 4, and 5. The longitudinal motion described need not beconstant, but can be omitted or its rate changed in some other manner sothat two or more turns of the coil can be placed more or lesssideby-side (as shown in FIG. 20).

In accordance with the invention, the coils can be wound of wire orformed of other conducting material and deposited as they are formed ona surface of paper, insulating board, ceramic, or other suitablematerial, which material can be rigid or flexible. Adherence to thesurface can be brought about by the use of a sticky matrix material onthe surface, by heat softening the surface itself, by casting onto thesurface material as it is formed, or by continuous or spot-appliedadhesive of any suitable kind. If a flexible surface, such as paper, isused, it is then possible to bend the coil into any desired shape as,for instance, in forming it around the neck of a cathode ray tube.

Alternately, such coils can be wound of wire or other conductor materialstiff enough to stand in whatever shape is desired without support orwith support at the ends or at selected points. It can also bemanufactured with one or more strips of plastic or other materialcontinuing longitudinally along the coil and embedding or otherwisesupporting a part or parts of each turn or some of the turns. Suchstrips can contain powdered or other core material to enhance the coil sinductance or its coupling to other coils. When the alternative methodshown in FIGS. 13, 14, and is used, the coils are formed by printing oretching techniques. A circuit board or surface can be printed or etchedor otherwise processed omitting one conductor at each of the coilcrossings. An insulating paint or other substance can be applied to-theintermediate crossing area and then a third step can be used to print ormount or form over the insulated area a crossing conductor and bondingit by suitable means to the end of the conductor to make a continuouscoil.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent 1. An electrical coil, comprising a.a strand of conductive material formed into a series of loops lyingsubstantially in the same plane to produce a field substantiallyperpendicular to the plane, each loop overlapping the loop preceding itand the loop following it in the series, the center lines of the loopslying in a straight line, and b. means insulating the strand from itselfat points of crossing. 2. An electrical coil as recited in claim 1,wherein the series of loops is encapsulated in a flat plate of plastic.

3. An electrical coil as recited in claim 1, wherein a core envelops theseries.

4. An electrical coil as recited in claim 1, wherein the series isassociated with another similar series lying in a spaced plane.

5. An electrical coil as recited in claim 4, wherein the 8. An electriccoil as recited in claim 1, wherein each loop is in the shape of apolygon.

9. An electric coil as recited in claim 4, wherein the coils are movablerelative to each other to change the magnetic coupling between them.

* III t

1. An electrical coil, comprising a. a strand of conductive materialformed into a series of loops lying substantially in the same plane toproduce a field substantially perpendicular to the plane, each loopoverlapping the loop preceding it and the loop following it in theseries, the center lines of the loops lying in a straight line, and b.means insulating the strand from itself at points of crossing.
 1. Anelectrical coil, comprising a. a strand of conductive material formedinto a series of loops lying substantially in the same plane to producea field substantially perpendicular to the plane, each loop overlappingthe loop preceding it and the loop following it in the series, thecenter lines of the loops lying in a straight line, and b. meansinsulating the strand from itself at points of crossing.
 2. Anelectrical coil as recited in claim 1, wherein the series of loops isencapsulated in a flat plate of plastic.
 3. An electrical coil asrecited in claim 1, wherein a core envelops the series.
 4. An electricalcoil as recited in claim 1, wherein the series is associated withanother similar series lying in a spaced plane.
 5. An electrical coil asrecited in claim 4, wherein the two series lie on opposite sides of anelectron-stream device for the purpose of controlling the stream.
 6. Anelectrical coil as recited in claim 4, wherein a shielding element ismounted between the two series to permit an adjustment of the mutualinductance between them.
 7. An electrical coil as recited in claim 4,wherein a core extends between the two series, and wherein the number ofcoils in the series are selected to provide a transformer.
 8. Anelectric coil as recited in claim 1, wherein each loop is in the shapeof a polygon.